Do we have the power?
Thermal & Energy management
This HIKARI activity focused on assessing different options and developing a complete thermal and energy management system.
For hypersonic cruise vehicles, and particularly for civil transport airplane, the thermal management for the overall system is a key point. As a matter of fact, it is mandatory to provide all needed cooling for passenger cabin but also for on-board equipment while facing very high heat fluxes on the external surface of the fuselage as well as inside the propulsion system. More precisely, the produced high heat fluxes related with high-speed flights friction, will have to be carried away to avoid too high structural temperatures within the vehicle and in particular for the passengers’ cabin, where the ambient temperature needs to be well regulated within narrow margins. Fuel is the only cold source on-board and has to absorb the main part of the heat entering the vehicle.
At the same time, during the main part of the flight (hypersonic acceleration, cruise and deceleration), the dual-mode ramjet propulsion system is not able to directly provide mechanical or electrical power to supply all energy consumers on board (up to ~1MW).
HIKARI provided a clear view on the different elements which can contribute to absorb the massive heat fluxes entering the vehicle from atmosphere during the long high-speed cruise: on-board thermal to electric energy conversion, fuel preheating and self-pressurization.
After having reached a good understanding of potential use of these elements, a global optimization approach allowed defining the best combination of such technologies to provide an efficient thermal and energy management ensuring suitable environment for passengers and on-board subsystems all along the trajectory.
Illustration of a potential cooling cycle
Regarding the energy and thermal optimization, the technology progresses accomplished within HIKARI, both on the modelling side and on the demonstration side provide credible building blocks to the future aircraft concept. Furthermore, these technologies offer real synergies with other industries, and promising short term applications.